#include<bits/stdc++.h>
//#define int long long

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);

    int T;std::cin >> T;
    while (T--)
    {
        int n;std::cin>>n;

        std::vector<int> a(n+1,0),cnt(n+1,0),suf(n+1,0);
        for(int i = 1;i<=n;++i)std::cin>>a[i];

        std::priority_queue<std::pair<int,int>> Q;

        for(int i = n;i >= 1;--i)
        {
            while(Q.size() && Q.top().first == a[i])Q.pop();
            if(Q.size())suf[i] = Q.top().second;
            cnt[a[i]]++;
            Q.push({a[i],cnt[a[i]]});
        }

        int ans = 0;
        for(int i = 1;i<=n;++i)
        {
            int x = cnt[a[i]],y = suf[i],z = x & y;
            //std::cout<<x<<" "<<y<<" "<<z<<"\n";
            while(z - (z & -z) > 0)z -= (z & -z);
            z = std::max(z,1);
            ans = std::max(ans,(x | y) | (z - 1));
        }

        std::cout<<ans<<"\n";
    }

    return 0;
}